The Roux-en-Y Gastric Bypass
is designed to reduce food intake by limiting the capacity of the stomach. A staple line is placed across the upper stomach and the stomach is divided, creating a small reservoir or "pouch." This smaller "pouch" is about as large as a medium sized egg. With a smaller stomach reservoir, you will feel full after eating a very small amount. This will reduce your hunger level and help you to reduce your food intake.
The procedure also creates a small opening or "stoma" between the stomach and small intestine. This stoma is about one-half inch in diameter, or less than the size of a dime.
This small opening into the intestine causes the stomach pouch to empty slowly and therefore you will feel full for a longer period of time. Food that is not chewed thoroughly can sometimes get stuck in this opening and cause obstruction of the stomach pouch and can result in discomfort, nausea and vomiting.
The Roux-en-Y component of the operation bypasses approximately 200 centimeters of the upper small intestine, thus reducing absorption of calories. If you consume too much of a highly concentrated sugary food or beverage such as milkshakes or candy, this fluid may empty too fast ("dump") into the small intestines and cause dizziness, weakness, sweating, cramps, and sometimes diarrhea. This is so-called "Dumping Syndrome."
Remember that these changes in the way your body tolerates and processes food are the intended consequences of the surgical procedure. They are designed to force you to alter your eating habits. The idea is for you to change your eating behavior rather than try to overcome the effects of the bypass procedure.